btrfs drive replacement

Referencing: https://lemmy.world/post/17588348

I want to make a NAS with a 500GB boot drive and 2x16TB HDDs. Based on my previous post, btrfs is a good option. It also looks easy to get started. My plan for the NAS would be to purchase several 16TB drives, and only use 2 of them.

My first question is about different drives. Could I purchase two different brand drives and use them with btrfs? (I assume yes)

2nd question: how does the replacement process go? Like if drive A died, so I remove it, and put a brand new replacement in. What do I have to do with btrfs to get the raid 1 back going? Any links or guides would be amazing.